identify
extern status_t identify(BMessage *settings, BPositionIO &stream, uint8 &type, int32 &bitsPerPixel);
if (ICO::identify(ioExtension, *stream, type, bitsPerPixel) != B_OK)
extern status_t identify(BMessage *settings, BPositionIO &stream, uint8 &type, int32 &bitsPerPixel);
if (PCX::identify(ioExtension, *stream, type, bitsPerPixel) != B_OK)